Carbon Dioxide → 1,4-Cyclohexane diisocyanate

Participants

Reaction Conditions

Reaction Steps

Carbon dioxide was added subsurface to a dichloromethane (30 mL) solution containing 1,4-diaminocyclohexane (mixture of cis and trans, 0.02 mol 2.30 g) and triethylamine (0.12 mol, 12.0 g) at -10° C. (ice and salt bath) for 40 min at a pressure of 0 psig. The reaction mixture was transferred rapidly via cannula under carbon dioxide to the precooled solution of phosphorus oxychloride (0.04 mol, 6.2 g) in 30 mL dichloromethane. After stirring for ca. 30 min at -10° C. a white ppt formed. The ppt. was filtered off and the filtrate concentrated in vacuo. The residue was extracted with 3×30 mL diethyl ether. The ether layers were concentrated and the residue was distilled under vacuum (ca. 0.1-0.3 torr) collecting product, 1,4-cyclohexyl di-isocyanate, at 68°-78° C. (2.0 g, 60%) of 99% purity as judged by GC. IR (neat) 2266 cm-1. 1H NMR (CDCl3) δ 3.61 (br, 2H), 2.03-2.01 (m, 1H), 1.86-1.70 (m, 6H), 1.54-1.50 (m, 1H) ppm.

Provenance & Evidence